1. Field of the Invention
The present invention relates to a control device of a premix combustion engine coupled with a hybrid turbocharger. Hereby, the control device also unit an engine control-device system including, but not limited to, the engine, the hybrid turbocharger and the control device.
2. Background of the Invention
According to a conventional technology such as disclosed by Patent Reference 1, a control device of a premix combustion engine 1 coupled with a hybrid turbocharger connected to a motor generator is publicly known. As shown in FIG. 4, with regard to the control device of the premix combustion engine 1 disclosed by Patent Reference 1, the charge air inlet 1b of the premix combustion engine 1 is connected to a compressor 2a and a fuel tank 3, and an exhaust gas outlet 1c of the premix combustion engine 1 is connected to a turbine 2b. Further, a rotating shaft 2c of the turbocharger 2c connects the turbocharger to a motor generator 4 that has a motor function as well as a generator function. The turbocharger 2 coupled with the motor generator 4 forms a hybrid turbocharger. A generator 5 is connected to the premix combustion engine 1 via a rotating shaft 1a; the generator 5 is provided with and connected to a detected unit 6 for detecting the charging airflow rate regarding the premix combustion engine 1 and the electric power generated by the generator 5. The detected signals from the detected unit 6 are transferred to a control unit 7, which transmits changeover signals toward the motor generator 4 so as to change the motor function to the generator function and vice versa.
In the next place, with reference to FIG. 5, the control method of the premix combustion engine 1 is explained. In the step S1 after the premix combustion engine 1 started, the control unit 7 reads the detected signals from the detecting unit 6; in the next step S2, it is judged whether or not the charging airflow rate (delivered by the turbocharger 2) is the right amount, based on the detected signals from the detecting unit 6, as well as, based on the data stored in the memory section in the control unit 7. In the next step S3, when the airflow rate is in shortage, the control unit 7 issues a changeover signal toward the motor generator 4 so that the motor generator 4 serves the motor function. In starting the premix combustion engine 1, the motor generator 4 receives the changeover signal to put the motor generator 4 under the motor function; then, the motor generator 4 acts as a motor. Thus, the motor generator 4 is driven by the electric power sent through an electric power line 8. Driving the motor generator 4 starts the operation of the turbocharger 2, via the rotating shaft 2c, When the turbocharger 2 is operated in this way, the charging air of an appropriate airflow rate is supplied to the premix combustion engine 1; and, the starting performance regarding the premix combustion engine 1 is enhanced. In addition, the stable operation regarding the premix combustion engine 1 is achieved from the engine start.
Further, when it is judged that the charging airflow rate is in shortage during the operation of the premix combustion 1, the control unit 7 issues a changeover signal toward the motor generator 4 so that the motor generator 4 serves the motor function, in the step S3.
On the other hand, when it is judged that the charging airflow rate is excessive, the control unit 7 issues a changeover signal toward the motor generator 4 so that the motor generator 4 serves the generator function, in the step S4; thereby, even if the rotation speed of the turbocharger 2 is excessive in response to the excessive charging airflow rate, the driving power thereof is utilized as the generating power energy for the motor generator 4, in the step S4.
Further, when it is judged that the charging airflow rate is appropriate, the control unit 7 de-energizes the function changeover signal toward the motor generator 4, in the step S5; receiving the de-energized function changeover signal from the control unit 7, the motor generator 4 stops serving the motor function or the generator function.
As described above, when the charging airflow rate is in shortage, the motor generator 4 serves the motor function so as to drive the turbocharger 2; hence, the starting performance regarding the premix combustion engine 1 is enhanced. Further, when the charging airflow rate is excessive, the motor generator 4 serves the generator function so that the motor generator 4 receives the driving power from the turbocharger 2 and generates the electric power; accordingly, the energy utilization performance regarding the premix combustion engine 1 is enhanced. Further, when the operation of the premix combustion engine 1 is controlled so as to appropriately maintain the charging airflow rate, the premix combustion engine 1 can be free from incomplete combustion due to the excessiveness or shortage regarding the charging airflow rate. In this way, the premix combustion engine 1 is controlled; and, when the control is finished, the airflow control regarding the premix combustion engine 1 is stopped, in the step S6. In a case where the control is continued, the step S6 returns to the step S1.